Base58 Encoder and Decoder

What is Base58?

Base58 is a binary-to-text encoding created for Bitcoin. Its alphabet is the 62 digits and Latin letters minus four characters that are easy to confuse: 0 (zero), O (capital o), I (capital i) and l (lowercase L). It also has no +, / or =, so a Base58 string can be selected with a double click and placed in a URL without escaping.

Unlike Base64, Base58 does not cut the input into bit groups. The whole input is treated as one large number and written in base 58, so there is no padding and a change in one byte can alter many output characters. Leading zero bytes have no numeric value, so each one is written as the first character of the alphabet (1 in the Bitcoin alphabet) to keep it. The output is about 1.37 times the size of the input.

Where Base58 is used

• Bitcoin. Legacy addresses and WIF private keys are Base58Check: Base58 with a version byte and a checksum.
• IPFS. A version 0 content identifier (CIDv0) is the Base58 form of a SHA-256 multihash, which is why those CIDs are 46 characters long and start with Qm.
• Solana. Public keys, account addresses and transaction signatures are written in plain Base58, without a checksum. A 32-byte key usually becomes 43 or 44 characters.
• Flickr and the XRP Ledger. Flickr short links use the Flickr alphabet, and XRP addresses use the Ripple alphabet, which is why they begin with r.

To move between Base58 and raw bytes, use Base58 to Hex and Hex to Base58. For identifiers that only need to be alphanumeric, compare Base62.

Base58 alphabets

All three use the same 58 characters in a different order, so a string encoded with one alphabet decodes to different bytes, or fails, with another.

Base58 in code

# Python (pip install base58)
import base58
base58.b58encode(b'hello')      # b'Cn8eVZg'
base58.b58decode('Cn8eVZg')     # b'hello'

// JavaScript (npm install bs58)
import bs58 from 'bs58';
bs58.encode(new TextEncoder().encode('hello'));